The chromosome-numbers of females in two dragonet fish species, Callionymus beniteguri and C. ornatipinnis, are thirty-eight (2n=38), all being subtelocentric in morphology. In the males of these two species, however, the chromosome number is thirty-seven (2n=37), among which one chromosome is of large metacentric in morphology. Two haploid chromosome numbers, n=18 and 19, are found to occur in the secondary spermatocytes. In the latter with n=18, one large metacentric chromosome is always present in any cell. The metacentric element observed in somatic and germ cells is suggested to be the Y chromosome. Thus, the sex-chromosome mechanism in these two species is inferred to be a multiple system, being an X1X2-X1X2 mechanism in the female, and an X1X2-Y in the male.
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Murofushi et al. (1983) studied this question.